Latrodectus geometricus
(Brown Widow Spider)

Taxonomic Hierarchy

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Arachnida
  • Order: Araneae
  • Suborder: Araneomorphae
  • Family: Theridiidae
  • Genus: Latrodectus
  • Species: Latrodectus geometricus

Common Name (AASMore information icon)

Brown Widow

Other Common Names

Gray Widow, Widow Spider, Brown Button Spider, Geometric Button Spider, Hourglass Spider, Cobweb Spider, Cob Web Spider, Comb-footed Spider, Tangle-web Spider, Gumfoot-web Spider

Author

Carl Ludwig Koch, 1841

Pronunciation

laa-tro-DEK-tuhs jee-oh-MEY-trih-kuss

Identification Traits

Disclaimer: The following table provides a quick overview of the spider's basic attributes. The physical traits are greatly generalized in order to aid in the identification and sorting of spider species using our search feature. This information is not exhaustive, and keep in mind that traits such as color, markings, and overall size and shape can vary widely within a species due to variables such as the spider's age, gender, diet, hydration level, climate, and habitat. Though experienced arachnologists and hobbyists can often classify spiders rather accurately based on their unique markings and general appearance, it's important to know that scientifically accurate spider identification relies on detailed taxonomic keys and microscopic examinations of a spider's reproductive organs.

Female iconFemale Male iconMale
Body size More information icon 7mm - 10mm 2mm - 3mm
Eye count 8
Primary Colors
Identifying Traits Smooth or shiny appearance, Spherical body, Unique pattern, Striped or banded legs, Especially long legs
Web style Cobweb


Additional Remarks

  • Not the only “widow spider” in North America; there are also four other species of Latrodectus.
  • This spider may be common in yards and gardens, sometimes building its web in more exposed situations than other species of Latrodectus.
  • Egg sacs are brown or beige spherical tufted/spiky objects that may be the best clues in identifying this species when the spider itself is not present (no other species of widow creates spiky egg sacs). Each one is ~10 millimeters in diameter and contains anywhere from 80-150 eggs; the species is very prolific, with females producing up to 20 sacs in their lifetime.
  • The venom of this species is potentially dangerous to humans, but the spider itself is timid and non-aggressive. Like other species of Latrodectus, its venom is neurotoxic, and while it’s likely to be just as potent as that of other widow spiders, it’s thought that they inject far less venom and bites usually only result in localized pain and swelling.
  • The spider can be mistaken for the “Common House Spider,” Parasteatoda tepidariorum. Check for a red or orange hourglass marking on the underside of the abdomen, which is present on Latrodectus but not on Parasteatoda. The eye arrangements and egg sacs are also very different between the two types of spider.

Featured Pictures

Picture of Latrodectus geometricus (Brown Widow Spider) - Dorsal Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Lateral Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Female - Dorsal Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Female - Dorsal Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Female - Ventral Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Egg Sacs Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Egg Sacs Enlarge picture icon
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Picture of Latrodectus geometricus (Brown Widow Spider) - Female - Dorsal Enlarge picture icon
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